This invention relates generally to a binder for retaining sheet material, that allows the user to access individual sheets, for removals or additions. Binders generally include a cover or backing member which is folded or bent along parallel lines to form a front section, a rear section, and a center spine section interconnecting the front and rear sections, and a mechanical binding mechanism fixedly attached to the backing member.
Binders of the type herein are typically used to retain rectangular sheet material having three holes punched along one edge. One popular binding mechanism comprises a post bar assembly having a three-rod ladder configuration for holding the sheet material, mounted by way of a hinge assembly to the rear section, adjacent to the spine, and further comprises a retaining or locking assembly mounted by way of another hinge assembly to the front section of the backing member. In this mechanism, the post bar assembly has a transfer bar, and swings on the hinge assembly to meet with a locking assembly having a locking bar that slidably and removably connects to the transfer bar.
Another binding mechanism comprises a three-ring assembly mounted to the spline or rear section of the backing member, and having a toggled joint for opening and closing the rings to provide access to the sheet material. The toggled joint is actuated by releases at either or both ends of the assembly, or by pulling and pushing the rings themselves. These binding mechanisms are referred to herein as "binding assemblies".
Heretofore, binding assemblies were mounted to the cover by rivets, accordingly leaving the heads of the rivets exposed on the outer surface of the cover or backing member. For example, in the post and lock bar binder, the hinge assemblies are typically connected by rivets to the respective front and rear cover sections. In the three-ring binder, rivets are placed through the binder, between the rings, and typically attached to the spine section of the cover.
These exposed rivets present a number of drawbacks, including an unaesthetic and unattractive appearance, requiring, in the past, the additional application of an outer cover to hide the rivet heads.
Heretofore, an alternative to the outer cover was provided by the use of a fabric hinge, in which the metal hinge strips of the post and lock bar binder are replaced with strips or layers of fabric material glued to the cover and binding mechanism, wherein the fabric material itself serves as the hinge assembly. Although obviating the need and use of rivets, this fabric hinge, like rivets, possesses a number of drawbacks. Fabric hinges lack durability in comparison to metal hinge assemblies, are labor intensive, and do not lend themselves to the use of automated equipment in assembly.
These drawbacks are effectively eliminated through use of the instantly disclosed and claimed improved binder for sheet material.
It is, therefore, an object of the present invention to provide a strong, durable and non-labor intensive connection mechanism for attaching the hinge assemblies, or three-ring binder mechanisms to the cover, which substantially improves the length of service of the binder.
It also an object of the present invention to provide a binder with no exposed fasteners on the outer surface of the cover, thereby eliminating the need for application of an outer cover.
It is still a further object of the present invention to provide a binder mechanism that can be simply and effectively attached to a cover after the cover is produced with automated equipment, and with a minimum of hand labor.